A memory device having a three-dimensional structure has been proposed in which a memory hole is made in a stacked body in which multiple electrode layers are stacked, and a charge storage film and a semiconductor film are provided to extend in the stacking direction of the stacked body in the memory hole. The electrode layers of the stacked body are gate electrodes of a drain-side selection transistor, a source-side selection transistor, and memory cells. The memory device includes the multiple memory cells connected in series between the drain-side selection transistor and the source-side selection transistor. The structure in which the drain-side selection transistor, the multiple memory cells, and the source-side selection transistor are connected in series is called a memory string. A slit that reaches the substrate from the upper surface of the stacked body is made in the stacked body. A conductor is filled into the slit. For example, the conductor is used to form a source line of the memory string. It is desirable to cause the cell current to flow quickly from the memory string toward the source line.